1. Field of the Invention
This invention relates to a locking mechanism for a connector which is used for connection of a wire harness for a vehicle and has a locking arm to be engaged with an engaging portion of a complementary connector.
2. Description of the Related Art
FIGS. 6 and 7 show an example of a technique related to such a kind of locking mechanism, which has been proposed by the applicant of this application and is disclosed in JP-A-6-89756.
As shown in FIG. 6, a male connector 50 which it to incorporate a female terminal 68 has a hood 53 at its front half 51 in the longitudinal direction. An arch-shaped swelling wall 54 is formed outside and integrally to the hood 53. A ring-shaped space 55 corresponding to a complementary female connector 65 is formed inside the hood 53.
Inside the swelling wall 54, a locking arm 56 to be engaged with the engaging portion 67 of the female connector 65 is formed. The locking arm 56 faces the ring-shaped space 55 and is formed in a direction of coupling a pair of connectors 50 and 65.
As seen from FIG. 7, the locking arm 56 includes a body 57 having a fulcrum 57a connected to a housing body 62 of the male connector 50, a coupling portion 58 which extends forward in the direction of coupling the male connector 50 from the body 57, and a pressing operating portion 59 which extends reward in the direction of coupling the male connector 50 from the fulcrum 57a. 
The body 57 is located between the coupling portion 58 and the operation portion 59. The body 57 has a thickness greater than that of the coupling portion 58. The fulcrum 57a is located at the rear portion of the body 57, and extends over the entire width of the body 57. The fulcrum 57a serves as a rotating furculum when the operation portion 59 is pressed.
The coupling portion 58 is formed from a thin flexible plate, and its tapered tip 58a is connected in an inverted -shape to the front end 54a of the swelling wall 54. The width of the connected portion extends over the entire width of the tip 58a. A warping space 60 is formed between the upper face 58b of the coupling portion 58 and the swelling wall 54.
A locking projection 61 (FIG. 6), which corresponds to a locking portion 67 of the female connector 65, projects downward from the lower face 58c of the coupling portion 58. The locking projection 61 is located in the vicinity of the tip of the coupling portion 58. The locking projection has a tapered guiding face 61a at its front and a locking face 61b at its rear.
The female connector 65 which is to incorporate a plurality of male terminals (not shown) is provided with a hood 66. The pair of connectors 50 and 65 are coupled with each other by fitting the hood 66 in the ring-shaped space 55 of the male connector 50. A locking portion 67 which is to be engaged with the locking projection 61 of the locking arm 56 projects from the outer wall of the hood 66. The pair of connectors 50 and 65 are locked to each other by bringing the locking projection 61 of the locking arm 56 into contact with the vertical locking face 67a of the locking portion 67.
As described above, the locking of the above connectors is performed by pushing the female connector 65 into the ring-shaped space 55 of the male connector 50. In this case, the front end 66a of the hood 66 intrudes while it is in contact with the locking projection 61 of the locking arm 56 so that the locking portion 67 floats the locking arm 56 in a ^-shape. The female connector 65 advances further deep. When the locking portion 67 completely climbs over the locking projection 61, the locking arm 56 is elastically restored. Thus, the connectors are locked to each other.
The locking is released by pressing the operation portion 59 of the locking arm 56. Specifically, when the operation portion 59 is pressed, the locking arm 56 warps in an arch at the fulcrum 57a according to the principle of a lever. The locking between the locking portion 67 and the locking projection 61 is released so that the pair of the connectors can be extracted from each other.
However, the connector described above presents the following problem to be solved.
First, when the locking arm 56 is floated in an arch by pressing the operation portion for coupling the pair of connectors 50 and 65 and its release, the locking projection 61 is not deformed vertically, but deformed on the skew or to draw a circular locus. This may arise a backlash between the connectors 50 and 65.
The occurrence of the backlash makes it impossible to maintain the intimate contact between the connectors 50 and 65. Particularly, in a waterproof connector, a water drop or dust will invade from the gap so that poor connection occurs. The reliability of the electric connection will be impaired.
The locking arm 56 is supported at two points of the furculum 57a and the coupling point 58. Therefore, when it suffers external force in the direction (width direction) orthogonal to the longitudinal direction, it is in the bended state due to no wall or member for stopping the external force. Thus, the locking arm 56 may be deformed in the width direction.